Memorable Motorcycles Bridgestone GTO

Our Memorable Motorcycles expert, Frank Melling also is the organizer of the British vintage motorcycle extravaganza known as Thundersprint. Melling began riding five decades ago and remains as much in love with motorcycles as when he drove his first bike into a cow shed wall aged ten. In the last 50 years, Melling has competed in every form of motorcycle sport and now declares himself to be too old to grow up and be sensible.

There are some motorcycles which, even when static, produce a tingle in any motorcyclist. The Bridgestone GTO is one of these bikes. Technically advanced, beautifully finished and with dynamic, original styling the 345cc disc-valved twin was state of the art when launched in 1966 – and looked it! Yet, by 1970, production had ceased and Bridgestone no longer made motorcycles at all. Why?

The folk story is that by 1970 Bridgestone were the primary supplier of OEM tyres to the big four Japanese motorcycle manufacturers – Honda, Suzuki, Yamaha and Kawasaki. The legend goes on to say that Bridgestone executives were taken for a quiet drink one night after work and told that if they continued to make such outstanding motorcycles they would lose the tyre business. It’s a lovely tale – but probably with little truth in it. In fact, Bridgestone’s withdrawal from motorcycle production has more links with other manufacturers, like Vincent and Brough Superior, who also tried to make “the best bike in the world – and hit the inevitable financial brick wall which comes from tiny production runs.

The Bridgestone name comes from an Anglicisation of the firm’s founder’s name: Shojiro Ishibashi. Translated into English, Mr. Ishibashi’s name is “Stone Bridge”. A snappier version became “Bridgestone”. Mr. Ishibashi was Japan’s first manufacturer of rubber soled footwear and began mass production in 1925. After the Second World War, Bridgestone began making a massive range of rubber products – and the success of a nascent motorcycle industry caught their attention, probably because they were already significant bicycle manufacturers.

Bridgestone only ever had a tiny production output compared with the major manufacturers and this meant that its products were much more expensive.

The first Bridgestones were ultra lightweight, 26cc motorised bicycles feeding post-war Japan’s need for practical commuter vehicles. By 1964 things had changed with Bridgestone producing a range of high quality lightweight motorcycles. With the closure of the Tohatsu and Lilac factories, Bridgestone found themselves in the position of being able to employ clever, experienced designers who would set the benchmark for innovative two-strokes.

It is rare to be able to make the statement that a motorcycle was definitively the best but in the case of the Bridgestone GTO, and its street styled sister the GTR, there was nothing in the world as technically sophisticated. The disc-valves allowed asymmetrical port timing on the two-stroke engine which, as a result, gave excellent torque. The 350cc bikes were neither gutless, overweight clones of bigger siblings, as was the case with European 350s, nor were they frantic screaming buzz boxes. In every way, riding a 350 Bridgestone is a sophisticated experience. The 37bhp motor, peaking at only 7,500rpm, gives true 100mph performance and this is competitive with any 1960s 500 sports bike.

Despite being air-cooled, the GTO is a quiet engine. Hard chromed cylinder bores allowed ultra-tight piston clearances and the phenolic lubricating discs offer perfect reliability – providing a close eye is kept on the fragile air-filter! Despite the disc-valved induction, the engine was narrow since Bridgestone positioned the alternator behind, and above, the cylinders. Only the six-speed gearbox, with neutral below first, was quirky in a less than efficient manner.

Despite being air-cooled, the GTO is a quiet engine. Hard chromed cylinder bores allowed ultra-tight piston clearances and the phenolic lubricating discs offer perfect reliability – providing a close eye is kept on the fragile air-filter!

Bridgestone made much of the bike’s finish – and justifiably so. A standard Bridgestone, with its powder coated frame, hand polished castings and triple chromed metal parts looked better than many show bikes – even after hard use. Inevitably, all this mechanical and cosmetic sophistication had a price – and this was the key to Bridgestone’s withdrawal from motorcycle manufacture.

Bridgestone only ever had a tiny production output compared with the major manufacturers and this meant that its products were much more expensive. The company also lacked the sophisticated dealer network of either Japanese rivals or BSA/Triumph in the vital American market whilst in Britain, the machines were distributed by just one dealer. Finally, motorcycle production was squeezed into one area of the rubber products factory and there was always pressure on space. Inevitably, the bean counters decreed that bikes had to go – a sad end to a range of outstanding motorcycles.